Apparatus for severing sheets from continuous webs



Sept 1, 1.936. c. T. HALL v APPARATUS FOR SEVERING SHEETS FROMCONTINUOUS WEBS Filed June 28, 1955 2 Sheets-Sheet l c. T. HALL2,053,030

APPARATUS FOR SEVERING SHEETS FROM CONTINUOUS WEBS Sept. 1, 1936.

Filed June 28, 1935 2 Sheets-Sheet 2 Patented sea. 1, 1936 STATES PATENTOFFIQE APPARATUS FOR SEVERING SHEETS FROM CONTINUOUS WEBS ApplicationJune 28, 1935, Serial No. 28,968 In Great Britain July 25, 1934 3Claims. (01. 164-68) This invention is for improvements in or relatingto apparatus for severing sheets from continuous webs, and it is anobject of the invention to provide a cutting apparatus which severs the5 Web at regular intervals.

It has previously been proposed to provide cutting mechanism forsevering moving webs of material such for example as tin or similarfoil, which apparatus comprises a rotatable knife arranged 10 toco-operate with a fixed knife in order to sever the web. The rotaryknife has usually been mounted on an arm attached to a rotatable spindleand is fixed to the arm by means of a pivot V which is offset from thespindle about which the 15 knife is rotated, and the knife is held inposition by a suitable spring. Whilst the knife is approaching thecutting point, means have been provided to load the spring and cause theforward movement of the knife to be retarded, and at a suitable timejust prior to the moment at which the web is to be severed, the springis released so that the knife springs forward with a snap action andco-operates with a fixed knife to sever the web with a quick movement.

25 According to the present invention there is provided a cuttingapparatus for severing lengths from a continuous web of material, whichcomprises in combination a rotary knife arranged to co-operate with afurther cutting element (for example, a fixed knife) said rotary knifebeing pivotally mounted upon an arm rotatable in timed relationship witha driven element and a cam follower connected with said pivoted portionof the knife and arranged to co-operate with a cam,

35 said cam being shaped to augment the movement of the rotary knife inthe direction of movement thereof whereby the web is severed whilst therotatable knife is moving at a speed greater than its normal speed ofmovement.

40 The invention will be more particularly described with reference tothe accompanying drawings in which:

Figure 1 is a sectional side elevation of a web severing apparatus.

45 Figure 2 is a plan of Figure 1.

Figure 3 is a View of Figure 1 looking in the direction of the arrow A,Figure 1.

Figure 4 is a plan view showing the operation of a portion of theapparatus.

50 Like references refer to like parts throughout the specification anddrawings.

Referring to the drawings, a continuous web I of material from whichlengths are to be severed is fed between a pair of feeding rollers 2 and3 55 which are operative to feed the web between the cutting elements.The cutting elements comprise a fixed knife 4 and a rotatable knife 5,and

the rotatable knife is pivotably mounted on an arm 6 which is fixed to arotatable shaft 1 driven through bevel gears 8 and 9 from the main driveof the machine.

The pin 10 about which the rotatable knife 5 is pivoted is offset fromthe shaft '1, and a cam follower H is attached to an extension [2 of theknife portion and is arranged to co-operate with 10 a fixed cam l3. Asshown in the drawings, the cam I3 is formed about the shaft '1 and isheld in a fixed position by being secured to the boss I4 of the bracketI 5. A spring I6 is provided to ensure that the cam follower is alwaysin contact with the cam face.

The operation of the apparatus is as follows: The rotatable knife 5 isrotated about the axis of the driven shaft 1, and as the cam follower IIruns round the cam I3, the knife 5 rotates at the speed at which theshaft 1 is driven until the cam follower H engages with the eccentricportion of lead l'l formed on the cam. Whilst the cam follower is inengagement with the lead I! the arm 6 rotates at the speed of the shaft1 and the knife 5 is caused to pivot about the pin ID in the samedirection as that in which the arm 6 is moving but at a greater speed.The cam 13 is arranged so that when the cutting operation is to beperformed the follower II is against the lead I! so that the speed ofmovement of the knife 5 is augmented during the cutting operation. Itwill be appreciated that the form of the eccentric portion ll of the cammay be varied as conditions require.

It will be seen from Figure 4 that the cutting edge l8 of the knife 5 isarranged to co-operate with the fixed knife 5 so that the web is severedin a manner similar to the cutting action of a pair of scissors.

What I claim as my invention and desire to secure by Letters Patent is:

1. In apparatus for severing lengths from a continuous web of material,the combination with a cutting element, of a positively driven rotatableshaft, a knife carrier rotatable in timed relationship with said shaft,a knife pivotally mounted upon said carrier, a cam having an abrupteccentricity in its contour at a point in advance of the point at whichsaid knife is operable to sever said web, and a cam follower secured tosaid knife carrier and adapted to cooperate with said cam to augment thespeed of said knife during the severing of the web.

2. In apparatus for severing lengths from a 7 carrier, a stationary camhaving an abrupt eccentricity in its contour at a point in advance ofthe point at which said knife is operable to sever said web, and a camfollower secured to said knife carrier and adapted to cooperate withsaid cam to augment the speed of said knife during the severing of theWeb. t V 3. In apparatus for severing lengths fronia continuous web ofmaterial, the combination with a cutting element, of a positively drivenrotat the web.

able shaft, a knife carrier secured to and rotatable with said shaft, aknife pivotally mounted on said carrier for rotation with the carrier, astationary cam having an abrupt eccentricity in its contour at a pointin advance of the point at which said knife is operable to sever saidweb, and a cam follower secured to said knife carrier and adapted tocooperate with said cam to move said knife about its pivot in thedirection of movement of the carrier, whereby the speed of the knife isaugmented during the severing of CHARLES THOMAS HALL.

